He imposed a custodial sentence of least 11 years and three months, with a five-year extension period subject to licence.

Umar Arshad, 24, and Syed Farhan Hussain, 22, were jailed for six years and nine months and five years and three months respectively for their roles in preparing a terrorist attack.

Security services had heard the four men discussing methods, materials and targets for a terrorist attack, the court heard.

Iqbal and Ahmed talked about making an improvised explosive device (IED) based on instructions in online al Qaeda manual “How to make a bomb in the kitchen of your mom – by the al Qaeda chef”, the court was told.

Covert recordings of the pair heard Iqbal suggesting attaching the bomb to a remote controlled toy car and sending it under the gap of an entrance gate at a TA centre in Luton.

Iqbal was recorded telling Ahmed: “I was looking and drove past like the TA centre, Marsh Road. At the bottom of their gate there’s quite a big gap.

“If you had a little toy car, it drives underneath one of their vehicles or something.”

The men were arrested following a series of raids at their homes in April last year after a joint operation by the Metropolitan Police Counter Terrorism Command and the British Security Service (BSS).

The court heard that Iqbal acted as a facilitator for people who wanted to travel for “extremist purposes” and had helped Ahmed travel to Pakistan in March, 2011 for military training.

Mr Wilkie said a further 13 counts relating to the possession of information contrary to the Terrorism Act 2000 should be left on the file.

Addressing Iqbal and Ahmed, Mr Wilkie said: “In each of their cases, their persistent commitment to terrorist activity, in a number of different ways, over a significant period of time and, in each case, their willingness to take practical steps to obtain terrorist training abroad, marks them as particularly dangerous.”